Information available from original sources are not to be construed as immune from discovery or use in any civil action merely because they were included in any report or analysis related to improving the quality, delivery, or efficiency of health care or for the purpose of credentialing or reviewing health care providers. Documents contained in peer review files are not discoverable on the basis that they were not created as part of the peer review process; rather, the document must be produced from the original source: Provided, That if the party seeking production can show that obtaining source documents will be unduly burdensome, the court may, in its discretion, order production of the nonprivileged documents contained in the peer review file.